libgcc_s.so 3.4 vs 3.0 compatibility

[Peter FELECAN]

Joe Buck <Joe.Buck@synopsys.COM> writes:

> On Tue, Apr 19, 2005 at 02:23:26PM +0200, Peter FELECAN wrote:
> > > > Currently the libgcc_s.so library has the same version in 3.4 and 4.0,
> > > > i.e libgcc_s.so.1 (SONAME = libgcc_s.so.1).
> > > > 
> > > > Is this as expected?
> 
> Jakub Jelinek <jakub@redhat.com> writes:
> > > Yes.
> 
> Peter:
> > > > Are the 2 libraries compatible? Interchangeable? Looking in the map
> > > > file, I don't think so.
> 
> Jakub:
> > > There is backwards compatibility.  So you want the latest libgcc_s.so.1
> > > from the compilers used to build your applications.
> 
> Peter:
> > I should understand that, as usual, there is no "backward"
> > compatibility. My worry being the case when somebody, having installed
> > 3.4 and 4.0, in this order, updates the previous compiler, 3.4, and
> > unknowingly replaces the latest library. For this, I think that
> > additional instrumentations are required by the corresponding
> > packages. Consequently, it is the role of the packager to assure an
> > hermetic separation.
> 
> No, I think you misunderstood Jakub.  If 4.0 is installed second, it will
> update the libgcc_s.so.1, and all the apps compiled with either compiler
> will continue to work.  You want to avoid the reverse situation, where 4.0
> is installed first and then 3.4.

Joe,

I understood Jakub. My fingers writing "backward" instead of
"forward" are wrong :-) Anyway, thank you for the comment which
confirms my understanding.

-- 
Peter FELECAN
mailto:pfelecan@acm.org